1. Technical Field
Embodiments of the present invention relate generally to electronic circuits and in particular to circuits for wireless communications.
2. Background
In wireless communication, the technique of frequency hopping is commonly used to ‘spread’ a signal over a spectrum range and reduce its susceptibility to noise or interference. Frequency hopping is one of two basic modulation techniques used in spread spectrum signal transmission, direct sequencing being the other. Frequency hopping is the repeated switching of frequencies during radio transmission and is often used to minimize the effectiveness of “electronic warfare”, or the unauthorized interception or jamming of telecommunications. Frequency hopping also is known as frequency-hopping code division multiple access (FH-CDMA). Conventional wireless technologies including Bluetooth, Wireless USB, WiFi, etc. use the technique of frequency hopping to send signals. A channel in radio communications typically means a specific frequency or band of frequencies used to establish a communications path between two communication stations. In frequency hopping, each frequency to which the stations hop is a channel. A frequency hopping system changes channels generally according to a predetermined sequence known to the transmitter and receiver, for example. Each frequency to which the stations hop is a channel, usually within a defined band of channels.
FCC regulations say that all channels should be used equally, that there should be no low energy channels. However, in most applications not all channels have the same level of quality or reception. Poor channels, defined as those with high error rate frequently drop data and require information to be resent. This may be adequate for data that is not time-sensitive (non-isochronous) such as email or file transfer, etc. However, poor quality channels are generally not suitable for time-sensitive data (isochronous) such as voice, video, music and streaming media.
It would be desirable to have a method for mapping isochronous data to higher quality channels having lower error rates and mapping non-isochronous data to lower quality channels with higher error rates.